In vehicles which are equipped with automatic transmissions, the shifting lever is movable from a park position to other gear positions such as reverse, neutral, drive, second gear, and first gear. The shifting lever is generally associated with a detent plate and a detent pawl for releasably holding the lever in the park position and an actuator means as provided for the driver to actuate the pawl to release the shifting lever for movement by the driver to the other gear positions.
In my U.S. Pat No. 5,096,033, issued on Mar. 17, 1992, I explained the problems that have been encountered in the unintended acceleration of a vehicle in shifting from the park position to the other gear positions. Therefore, efforts have been made to prevent the shifting of the shifting lever until the brake pedal had been depressed so that the vehicle does not move before it is intended by the driver.
My U.S. Pat. No. 5,096,033 discloses an electrically operated control module mounted on a detent plate and having a pin movable between a distended position to an extended position. This control module is controlled by the application or nonapplication of the brakes of the vehicle ill which the shifter is mounted. When the brakes are not applied, the pin is urged to all extended position which prevents a lockout arm from being moved by the actuation of the pawl actuator and, accordingly, the pin when extended prevents the shifting of the shift lever. However, when the pin is distended by applying the brakes, it is located out of the path of the lockout arm permitting the actuation of the pawl and the shifting of the shift lever from park position to the other gear positions.
Many other types of lockout mechanisms have been devised. One such suggested mechanism was to mount an electrically operated control module having a pin movable between a distended position to an extended position on the tube of a shifter lever. In such mechanism, the pin was movable in response to the energization of the coil of the module to an extended position and into the path of a pawl actuator. The pin actually was an armature forced by the magnetic field of the coil into a notch formed in the side of the pawl actuator locking the pawl actuator against movement by the driver. Both the pin and the notch included angled sides which engaged each other so that when the coil was not energized, the pin was cammed out of the way of the pawl actuator permitting the driver to move the pawl out of the park/lock position. In this proposed design, the axial center of the coil of the module and the pin extended along an axis perpendicular to the pawl actuator and the pin was held in the notch of the pawl actuator by a magnetic force and was withdrawn from the notch by a spring. This arrangement resulted in a temporary binding force between the pawl actuator and pin which gave an undesirable feel to the driver. As a result, it was contemplated to provide two similar modules spaced one above the other in an attempt to eliminate such binding. Such previous design also had the decided disadvantage of cost and requiring constant energization of the coils during the park/locked condition of the shifter.
The object of the present invention is to provide a simplified, lower cost version of a brake/park mechanism for preventing a driver from shifting a shift lever from park position to another gear position unless the brake is applied. Another object is to provide a brake/park/lock mechanism which can be used with the BTSI System of my U.S. Pat. No. 5,096,033 which will permit the shifter lever to be shifted out of the park position only when the brake is applied and the steering lock mechanism is released by actuation of the ignition key.